Method of operating reciprocating pumps.



H. M. & T. M. 0HAN()E. METHOD OF OPERATING REGIPROGATING PUMPS. APPLICATION FILED MAY 6, 1911.

1,026,638. Patented May 14, 1912.

Imam 60w COLUMBIA PLANOGRAPH CO.,WASHINOTON, uc.

"UNITED STATES PATENT CFFICE.

HENRY M. CHANGE AND THOMAS M. CHANCE, OF PHILADELPHIA, PENNSYLVANIA.

METHOD OF OPERATING RECIPROGATING- PUMPS.

Specification of Letters Patent.

Application filed May 6, 1911.

Patented May 14, 1912.

Serial No. 625,488.

To all whom it may concern:

Be it known that we, HENRY M. CHANCE and THOMAS M. CHANGE, citizens of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented. a certain new and useful Method of Operating Reciproeating Pumps, whereof the following is a specification.

Our invention consists of an improved method of operating double acting reciproeating pumps for pumping liquids or such mixture of liquids and gases, or liquids and solids as are capable of being pumped, and is applicable to any form of reciprocating pump which has two pump chambers, or one chamber divided into two compartments by a piston or plunger, and in which such compartment-s or chambers are provided wlth inlet valves or ports, and discharge valves 01' ports.

Our invention depends forits successful operation upon the functions of a moving body of liquid as described in an appllcation for patent for method of pumping l1qu1d Serial No. 575,669 filed Aug. 5th, 1910 by Thomas M. Chance in which the momentum of a moving body of liquid is used to draw in and to discharge liquid, and as also described in an application for patent for methods of pumping liquids, Serial No. 590,790 filed Nov. 5th, 1910 by Henry M. Chance and Thomas M. Chance in which the momentum of a moving body of liquid is used to draw in and to discharge liquid, but we do not herein claim the methods of operation described or claimed in those applications.

The improvement consists in imparting relatively high velocity to a confined body of liquid which is in free communication with two pump chambers, or with the two compartments of a pump chamber, of double acting reciprocating pump, and 1n causing the momentum of this body of liquid to discharge and to draw in liquid. This body of liquid thus becomes an oscillating liquid fly-wheel and may be applled to any such pump by connecting the two pump chambers by pipes or conduits so placed as to be kept full of liquid. The conduit (or conduits) should have a length greater than its diameter and should be large enough to permit free oscillations of the liquid, and to hold a body of liquid large enough to absorb and give out the energy required to be absorbed in the early part of the stroke and given out during the latter part of the stroke.

Figs. I and II show how a pump of a type in common use can be operated by our improved method, Fig. I being a vertical crosssection taken 011 the line CD of Fig. II, and Fig. II being a horizontal cross-section taken on the line AB of Fig. I.

In these drawings 1 is a pump chamber, containing a cylinder 2, with a pump piston 3, piston rod 4, packing gland inlet valves 6, 6, and discharge valves 7, 7, suction intake 8, air chamber 9 and discharge outlet 10, a conduit 11 filled with liquid connects the two subdivisions of the pump chamber 1. The piston-rod 4 is connected to any source of power by which reciprocating motion can be imparted to it.

The action of a pump so equipped will be as follows: If the initial pressure produced in the pump chamber at the commencement of the stroke be greater than the pressure to be pumped against, a portion of the liquid will be directly displaced through the discharge valves from the chamber in front of the piston, and a corresponding quantity of liquid will be drawn into the chamber behind the piston through the inlet valves of that chamber; at the same time movement will be imparted to the liquid in the conduit and the energy so stored will, after the end of the stroke, produce pressure in the chamber behind the piston, causing the discharge valves to open and some of the liquid will be discharged through them and at the same time a reduction of pressure will occur in the chamber in front of the piston and will cause the inlet valves of that chamher to open and liquid to flow in through these valves; if the initial pressure at the commencement of the stroke be less than the pressure to be pumped against, then none of the liquid in the chamber in front of the piston will be discharged through the discharge valves of that chamber, and all the available energy of the power stroke will be expended in imparting velocity to the body of liquid in the conduit, and the momentum of this body of liquid after the end of the power stroke will produce pressure in the chamber behind the piston sufiicient to open the discharge valves and force liquid through them, while the reduction of pressure in the chamber in front of the piston will cause the inlet valves of that chamber to open and liquid to flow in through them. This method of operating is especially useful when applied to steam-driven pumps. lVhen making such application it is desirable that the steam pressure used and the areas of the steam piston and water plunger or piston be so proportioned that the maxi mum pressure which can be developed in the water end by the steam before expansion is not in excess of, or is less than, the pressure head against which the pump is to operate. The steam cylinders of pumps so equipped should have the usual clearance to act as steam cushions to bring the piston quietly to rest at the end of its stroke, but hydraulic or other cushions may be substituted for these steam cushions.

This improvement when applied to pumps driven by steam or other expanding me dium, permits of very early cut-oft" and very high expansion of the expanding medium, and a pump so equipped will operate with early cut-off and with low mean effective pressure of the driving medium against relatively high pressure heads. This peculiarity of pumps so equipped makes it possible with a given steam pressure, and a given ratio of steam piston diameter to pump piston diameter, to pump economically and effectively against any pressure which will not break or deform the pump chambers, valves, pistons, packing, and other parts subjected to stress from such pressure.

lVe are aware that the application of what may be termed a liquid fly-wheel to double acting reciprocating pumps is not new, but the described method of operation differs from those heretofore used in that the oscillating body of liquid is directly connected to the pump chambers, and in that a portion of this body of liquid is discharged from the conduit and a new increment of liquid is taken in at every stroke of the pump.

Our improvement may be used with any form of double acting reciprocating pump, either piston or plunger, inside or outside packed, single or duplex and also with those forms of multiple chamber single-acting pumps in which pistons or plungers move in opposite directions in pairs in unison. The speed of operation of pumps so equipped will vary with the length and diameter of the conduit used, increase in diameter increasing the speed, and increase in length decreasing the speed, and vice versa,

and the diameter and length may therefore be proportioned to give any desired piston speed.

While the drawing, Figs. I and II, shows the oscillating body of liquid inclosed in a single conduit, we do not limit ourselves to this form of construction for it will be understood that the body of liquid may be inclosed in two or more conduits.

Having described our invention we claim:

1. A method of operating reciprocating pumps which consists in imparting relatively high velocity to a confined body of liquid which is in free communication with one chamber of said pump from which liquid is being expelled and is in free communication with another chamber of said pump into which liquid is being drawn, in causing the momentum of said body of liquid to discharge liquid from the last named cham her, to produce a region of low pressure in the first named chamber and to draw in a new increment of liquid into said first named chamber.

2. In a reciprocating pump the combination of a pump chamber, provided with an inlet valve and a discharge valve, another pump chamber, provided with an inlet valve and a discharge valve, and a conduit connected at one end with one of said pump chambers and at the other end with the other of said pump chambers.

In testimony whereof we have hereunto signed our names at Philadelphia, Pennsylvania, this fourth day of May 1911.

HENRY M. CHANGE. THOMAS M. CHANGE W'itnesses:

E. R. BARNARD, E. M. LnAcH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, I). C. 

